Stable and some radio isotope labeled compounds have been synthesized to support other laboratory projects. In particular, the possible melatonin metabolites 5-methoxyindole acetic acid (0-CD3); N-acetyl-5-methoxykynurenamine (0-CD3); and their ethyl analogues were prepared. Labeled analogues of N-methyl-4-phenyl- 1,2,3,6 tetrahydropyridine (N-CD3; 2,6-D2) were prepared as well as 3-H and 14-C analogues.